Interpretive Summary: There is a need to standardize laboratory testing for products designed to control bed bugs, though there are difficulties in rearing bed bugs and producing sufficient numbers for testing purposes. We compared the mortality of different stages (immature and adult) and sexes (male and female) of bed bugs to a commonly used insecticide to determine if any differences in mortality exist between these groups. We found no significant difference in mortality between adult male and female bed bugs. Therefore, we conclude that males exclusively can be used for efficacy testing, thereby preserving females for colony maintenance and expansion. This information will be used by and benefit people in academia, government and industry that are interested in developing new products to control bed bugs.

Technical Abstract:
Exposure of a pyrethroid-susceptible strain of bed bugs, Cimex lectularius L. (Hemiptera: Cimicidae) to varying concentrations of deltamethrin for 24h indicated there was no significant difference in mortality between males, females, and nymphs at 24h or 168h post-exposure. Most bed bugs classified as morbid or moribund at 24h, and removed to an untreated surface, recovered by two weeks and were capable of feeding when given the opportunity. Adult female bugs that didn’t die were able to lay eggs, and the resulting nymphs were able to blood-feed. By contrast, all bugs classified as morbid or moribund that remained on deltamethrin-treated surfaces for two weeks, either died or were still classified as morbid or moribund at the end of this time frame. No bugs classified as morbid or moribund blood-fed when given the opportunity at two weeks, regardless of whether they remained on the treated surface or were removed to an untreated surface.
Results also indicated there is little reason to assess efficacy beyond one week, even when bugs are exposed for only 24h. A power analysis indicated that we could detect small differences in mortality between male and female bugs. Since no such differences existed in this study, using males exclusively in efficacy assays is a suitable strategy to preserve females for laboratory colony survival.